Police in outer north-west Leeds have been warning motorists about passing too close to cyclists.
A police officer was cycling in plain clothes on Wednesday and passing information about any vehicles that were overtaking 'uncomfortably close' to uniformed patrol officers waiting nearby.
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The officer was cycling on Green Lane in Yeadon, Cookridge Lane in Cookridge and near Golden Acre Park.
Motorists passing too closely to cyclists were then offered an educational roadside course as an alternative to any potential prosecution.
The exercise was done with the help of Leeds City Council.
West Yorkshire Police's north west team said people in nine vehicles were spoken to about passing too closely, and four motorists were also dealt with for mobile phone offences.
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A police floor matt used for the educational course shows that a driver should give at least 1.5 metres' distance between the car and cyclist.
Cyclists are also advised to stay well away from the kerb for their own safety.
The Highway Code tells motorists to give cyclists 'plenty of room' — the same as they would when passing another vehicle — but no minimum distance has been set.
Passing distances have been introduced in many countries, with gaps of at least a metre on local roads, rising to 1.5 metres on faster routes.
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Police attribute 'passing too close to the cyclist' as a contributory factor in a 25 per cent of serious collisions between cyclists and large vehicles.
In 2017, there were 2,203 road collision casualties in Leeds and 55 cyclists were killed or seriously injured.
West Yorkshire Police was one of the first forces in the country to introduce a safe pass initiative in 2017.